Yet Another Cycling Forum
General Category => The Knowledge => Topic started by: Pedaldog. on 12 October, 2017, 02:12:18 am
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Om a "Town Bike" with 5 speed SA gears and hub brakes. i have a bottle dynamo, on the right fork and pointing forward. looking online I see options of right or left hand dynamos. As described above, which should I look for and can anybody recommend a decent, not too expensive, one to replace it with? ( it dunt werk! )
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Sounds like you need a RH dynamo but I don't know which current model would be a good choice. Nordlicht used to be decent. A lot of dynamo problems are due to faulty wiring, rather than a dodgy dynamo (bearings aside).
Apparently Nordlicht are (almost) no more.
https://www.dutchbikebits.com/nordlicht-dynamo
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to test the dynamo itself electrically, connect a short length of wire (a paperclip would do) between the live terminal ("+") and the bracket/return connection ("-").
Compare the effort required to turn the little wheel on the dynamo in your fingers, when the wire is connected (generator shorted) vs when it isn't. It should be a lot more draggy when the wire is connected.
If it is, look to the wiring or the bulbs/lamps for a fault of some kind, like LWaB says.
cheers
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I used an Axa one to power the lights on barakta's trike before modifying for electric assist. It seemed to do the job well enough, no problems with slipping, but didn't get a lot of wet-weather use.
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I had a Union bottle dynamo, like this: https://www.sjscycles.co.uk/dynamos/union-sidewall-bottle-dynamo-left-fitting/ (except mine was silver) back in 1986 or thereabouts. It was total crap! Very high drag, very low output. Avoid, even for a fiver!
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I had a Union bottle dynamo, like this: https://www.sjscycles.co.uk/dynamos/union-sidewall-bottle-dynamo-left-fitting/ (except mine was silver) back in 1986 or thereabouts. It was total crap! Very high drag, very low output. Avoid, even for a fiver!
YMMV. I'm an old git and I used these dynamos for years. Never had problems with slippage, noise, tyre wear or excessive drag. Back then the problems were from having to use incandescent bulbs - low output, contacts, blowing, etc. - LEDs have now eliminated these. It does pay to set bottle dynamos up carefully - radially, contact angle with the tyre, contact pressure, wiring and tyre choice.
I also used BB dynamos too (Union and Soubitez) and despite the old saw about them being vulnerable to road spray never had any problems - but I never used them without a decent front mudguard.
I prefer hub dynamos now but I'd have no hesitation in putting a Union dynamo on a Pub bike and I'd expect it to work reliably and efficiently. On a decent bike I'd be happy to fit a B&M one.
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BITD I had several bottle dynamos and they suffered all the problems listed above. They were so useless that I fitted a SA steel dynohub (weighs about 2lbs) and I used that for 50000 miles or more without issue. Its output was about 2/3rd that of a modern hub dynamo, but a quiet, reliable glow worm was infinitely preferable to a bottle dynamo or battery lights.
More recently I had a town bike with a bottle dynamo system (built in as a factory fit) and I had hoped that the intervening 30 years had improved matters, at least enough that it would be tolerable for short periods. Some hope. The generator (an AXA HR) was slightly less noisy/draggy but the connections gave all kinds of trouble (corrosion), it was still pretty draggy, it slipped, it wore the tyre, and the noise (which I like about as much as a dentist's drill) drove me berserk.
Finally (after a few thousand mile's actual use) it did the decent thing and killed itself by knackering the bearings. I did not mourn its passing. For me the typical journey with one running was only about five miles at a time, and it was such a miserable experience I really couldn't wait for it to be over.
How anyone routinely tolerates the blessed things for longer than that I cannot comprehend.
cheers
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YMMV. I'm an old git and I used these dynamos for years. Never had problems with slippage, noise, tyre wear or excessive drag.
+1. I used Nordlichts happily for decades in all weathers, except perhaps heavy, packed snow.